Ceres Up Close (and a Bit of Bradbury)

byPaul GilsteronJune 11, 2015

I know I’m going to remember the summer of 2015 for a long time. The confluence of deep space missions has brought new images every week, including the latest view of Ceres and its enigmatic bright spots, which appears below. I’m already bracing myself for that Voyager-like sense of deflation once New Horizons gets past Pluto/Charon and the long-anticipated targets dwindle. Pluto has a special place for some of us because we grew up with it being considered the ninth planet. Dwarf planet or not, it’s the final act of a classic Solar System tour.

Not that we won’t be returning to many of these places, but the timing is uncertain and once Juno finishes its work at Jupiter, we’ll have no missions on their way to the outer planets. That makes this summer both energizing and a bit poignant, but let’s enjoy it while we can. This view of Ceres, taken on June 6, really is spectacular. We’re seeing the dwarf planet from 4400 kilometers as Dawn flies its second mapping orbit. The resolution is 410 meters per pixel.

It’s the bright spots that continue to seize the imagination, as Chris Russell (UCLA), principal investigator for the Dawn mission, notes:

“The bright spots in this configuration make Ceres unique from anything we’ve seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon.”

The crater enclosing the brightest of the spots is about 90 kilometers across, and so far we have no clear explanation for where they appear or why they are as bright as they are. Like Vesta, Ceres reveals abundant cratering, but as this JPL news release makes clear, the latter shows a good deal more activity on the surface in the form of landslides and other flows. April’s color map, discussed at the 2015 General Assembly of the European Geosciences Union in Vienna, shows differences in color and terrain suggesting that Ceres was once an active body.

Image: This map-projected view of Ceres was created from images taken by NASA’s Dawn spacecraft during its initial approach to the dwarf planet, prior to being captured into orbit in March 2015. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The plan is for Dawn to continue in its 4400-kilometer orbit until June 28 before moving to 1450 kilometers, an altitude it will descend to in early August. The views, in other words, should continue to improve. Are we looking at an object that will one day become important to a system-wide infrastructure? John S. Lewis has suggested that Ceres could be a primary base for transport and operations in the asteroid belt, as well as a valuable stepping stone for the exploration of objects still further out, such as the icy moons of Jupiter and Saturn.

Working with Ken Roy and David Fields, Robert Kennedy has examined Ceres as a ‘shell world,’ one that could be ultimately transformed by being enclosed in a spherical shell of matter that could house an atmosphere and ecosystem. We’ve bandied the idea around extensively in the comments here ever since it was presented at the 2011 Tennessee Valley Interstellar Workshop session in Oak Ridge (see Terraforming: Enter the ‘Shell World’). The problems are formidable, but the authors note in a JBIS paper that a terraformed Ceres that is half ocean yields enough dry land to approximate the area of Indonesia, on a world with a gravity well only 1.5 percent that of Earth. Think of it as an enclosed micro-gravity tropic zone.

All of which, combined with this summer of deep space achievement, brings Ray Bradbury’s short story ‘Rocket Summer’ irresistibly to mind:

Rocket summer. People leaned from their dripping porches and watched the reddening sky.

The rocket lay on the launching field, blowing out pink clouds of fire and oven heat. The rocket stood in the cold winter morning, making summer with every breath of its mighty exhausts. The rocket made climates, and summer lay for a brief moment upon the land…

Such distant futures are fascinating in their own right and I applaud their exploration, but right now we’re in the midst of first-wave exploration by machine, and it’s clear that Ceres has many secrets yet to divulge, including the question of whether or not it has an internal ocean. Much rides on the outcome, but Ceres as refueling stop for Brian McConnell and Alex Tolley’s ‘spacecoach’ is an attractive proposition as we develop human missions to the outer planets.

The paper on terraforming Ceres is Roy, Kennedy and Fields, “Shell Worlds: An Approach to Terraforming Moons, Small Planets and Plutoids,” JBIS Vol. 62 (2009), pp. 32-38. John Lewis’ new book is Asteroid Mining 101: Wealth for the New Space Economy (WaveCloud Corporation, 2014).

Comments on this entry are closed.

HaroldJune 11, 2015, 9:51

The position of the largest bright spot in the center of the crater certainly looks like a central peak uplift for a complex crater. Is there any evidence that the crater is the youngest crater?

I haven’t seen a lot of the alternate theories for these spots – beyond a casual mention of “salt deposits”. I wonder too if these are fields of molten, glass-like material – again from a more recent impact perhaps?

The tricky part of course is that Ceres’s surface is quite dark overall and these images are over-correcting the exposure quite a bit. Can’t wait to see how it all unfolds.

Indeed Paul I’ve had the same feeling, one akin to the 70’s as our roaring space program came to a soundless halt. It’s not that we lack targets. But I’ve heard not a peep about Neptune and Uranus orbiters, surely an essential part of understanding our solar system. Even the Europe project is down-sized to near uselessness.

Alas, all eyes are on Mars. Each time Gen. Bolden says anything he tweets ‘#RoadtoMars’. And it’s too bad. In my mind our future lies outside the gravity wells.

Actually I am not surprised that Ceres has “impurities” on it’s surface.
It receives a substantial amount of solar energy . It rotates relatively fast at around 9Hr and the max surface temperature is 235K.
By comparison Mars has an average surface temperature of about 210K.
So it’s not like a sterile Jovian outer moon, such as Callisto.
It is not hard to imagine that a liquid compound with anti-icing elements is has broken through the surface and those elements when frozen are highly reflective.

I’m going to indulge in a bit of totally unscientific fantasy. In Kim Stanley Robinson’s “Icehenge” an enormous, enigmatic monolith is discovered on Pluto. And here with Ceres, it’s almost impossible not to think “ooh! ailyun bases!” when looking at those insanely bright spots. Admittedly, close-up they look a lot less artificial than they did at a distance, but still and all: it reminds me of Frederik Pohl’s wonderful novel “Gateway” in which an unremarkable asteroid is discovered to be full of abandoned (but functional) alien spaceships. So. To put it together, here’s my fantasy: What if we discovered evidence of ET on two small planets *simultaneously*?

Thinking along the lines of para-forming Ceres we could relax the surface keeping the dust on the surface then spray a thick metal coating onto the dust covering say from orbit to create an enclosed sphere. We could then build solar concentrators and cells to convert some of the ice beneath into oxygen, storing the hydrogen on the outer surface, to form an atmosphere within the shell. At the same time we darken the metal coating so that it captures the heat from the sun melting the ice beneath the shell, now as the ice melts it makes up a smaller volume as water allowing a substantial head space for the oxygen atmosphere. Later we can create windows to let light in and generate a magnetic field at the poles to deflect harmful radiation.

Now that would be a Mega engineering project for a huge fish farm.

I personally would love to see a rover/sample return from Ceres in my life time that’s for sure.

Looking at Ceres’ craters, I was reminded of the curious fact that illustrations of asteroids in most older astronomy books–not to mention depictions of them in science fiction stories (in words and images) and television shows–portrayed them *without* craters. In such a highly-populated area of space where collisions are more common, it seemed to me (even when I was very young) that impact craters on asteroids would be a given.

Perhaps I am being an optimist here, but I think there will be enough interest in this bright probably-icy-stuff, possible ice-geyser things that space agencies decide to send a lander, possibly a rover to Ceres’s surface. Getting to Ceres will be a lot faster next time around, surely they’ll go straight* there with chemical rockets. Yes, it would be really good if we could re-assign one of the upcoming Mars rovers to exploring Ceres, or more realistically re-use the base system with some appropriate changes

*okay, with possible gravity assists along the way – what I mean is no going into orbit around Vesta this time ;)

“Looking at Ceres’ craters, I was reminded of the curious fact that illustrations of asteroids in most older astronomy books–not to mention depictions of them in science fiction stories (in words and images) and television shows–portrayed them *without* craters. In such a highly-populated area of space where collisions are more common, it seemed to me (even when I was very young) that impact craters on asteroids would be a given.”

I agree but there is a good explanation for that. Remember that it took Apollo to definitively show that the Moon’s craters were due to impact cratering rather than volcanic calderas. Prior to the mid-sixties the consensus seemed to favour volcanic origins of craters and vulcanism should only apply to large bodies such as planets and large moons. Tiny potato shaped asteroids on the other hand shouldn’t show any volcanic calderas, so smooth they ‘should’ be.

So now that we know that impact cratering plays such a major role we see glaring evidence of it everywhere and with our hindsight we notice these dichotomies in how things were mis-represented back before major peices of the puzzle were solved.

I also think that we are lucky to have scientific artistic representations of space dating back well over half a century. What a trove… to be able to chart the ebb and flow of ‘current’ thinking in such a graphical form as ideas gelled and breakthroughs in knowledge steered our space-artists this way and that.

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last twelve years, this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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